mbs,
Have a look at Telkom's web site, specifically, the "Telkom Mobility" service they are offering.
This seems to be a reasonable VPN over ADSL solution. If they wanted to reduce costs for improved throughput, they might want to look at this, combined with DataPro uncapped ADSL at the main branch, any thoughts?
Gina,
If you have mission critical mail passing through your line, I would not move from Diginet, as the other services available are what Telkom calls "best effort" and there is absolutely no guarantee that anything will be repaired if something breaks.
If constant internet access is not absolutely essencial, you could consider connecting the DataPro Uncapped ADSL solution at your main branch, and using Telkom Mobility over ADSL to carry VPN traffic between your branches. You would also need to have an ISDN back-up at the main branch should the ADSL line fail, but then you might still be without your VPN.
If all you really want is a boost in bandwidth, there might be another solution for you.
It is possible to operate two links. You could keep the Diginet line as is, and use it for mission critical tasks, hosting, mail transfer, VPN, etc, and as a back-up link for web browsing.
Then, install an ADSL line as an additional link, either the DataPro uncapped service, or Telkom's capped offering. DataPro is highly recommended if you will need to be downloading a lot of files.
This is reasonably simple to set up. Leave the Diginet as the main default route for IP traffic in and out of your office, but set up a catch-rule on your router to redirect web traffic to a transparent proxy server. Squid, running on a UNIX machine with lots of RAM, lots of storage space and a processor with healthy performance specifications is highly recommended.
You can now use the transparent proxy to force-route your web traffic through the alternate connection. This will mean that your mission critical data will still travel via the stable and reliable, but slower, Diginet interface, and web traffic will travel via the faster ADSL interface when available.
The transparent proxy server will also act as a web cache, if set up to store large files, it will significantly improve your line usage efficiency, as the data for Windows updates, virus updates, etc, would only need to pass through your external line once, when first downloaded by one of your users, and from there on, will be served to the other users directly from the proxy cache. This will also greatly improve browsing speed on popular web sites, and web sites used frequently by your users.
Again, I should state that if you go for this option, I would most certainly recommend the DataPro uncapped offering. With the uncapped ADSL offering, you could route all your web traffic across the ADSL line without worrying about the cap, and set up network monitoring software to automatically remove the catch-rule from your router and route web traffic through the Diginet interface if they ADSL interface should drop for any reason. Many SNMP based tools are available to allow such automatic configurations.
With the Telkom offering, you would need to manually reconfigure your router to route the web traffic over the Diginet line each month, as soon as you have reached your cap, and change it back at the beginning of the next month. Most business users would find this unacceptable.
I hope this helps. If you would be interesting in trying a dual-link solution, I would be more than happy to help you set it up. Feel free to drop me a mail at any time.
Willie Viljoen
Web Developer
Adaptive Web Development
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